The use of data archiving systems to provide for online storage for computer processing systems that is separate from the primary or main memory of the computer processing system is well known. Examples of current secondary storage systems include magnetic disk drives, optical disk drives, magnetic tape drives, and solid state disk drives. Typically, secondary storage systems have much larger memory capacities than the primary memory of a computer processing system.
As the popularity of distributed computer networks has increased, the demand to store ever increasing volumes of data as remote files also has increased. In response to this demand, a number of remote secondary storage systems have been developed primarily for the purpose of storing remote files. These secondary storage systems, known as data servers, file servers or information servers, are not connected to an individual computer like a traditional secondary storage device; rather they are connected to the distributed network itself.
Most existing data servers either rely on individual users to manually perform back up of remote files or, when the amount of available secondary storage space falls below some minimum amount, use some type of least-recently used archival algorithm whereby all remote files that have not been accessed for a given period of time are archived to removable secondary storage devices. Unfortunately, neither of these techniques provides for an intelligent or reliable archiving of remote files. Those data servers that have individual users manually back up files usually end up requiring some type of network administrator intervention whenever the amount of available secondary storage space falls below the required minimum amount to effectively operate the network data server because users cannot be relied on to back up and then remove inactive remote files consistently. On the other hand, those data servers that automatically archive remote files that have not been accessed for a given period of time and blindly apply the archiving algorithm to all remote files, end up being unable to accommodate, for example, online storage of large or very large remote files that must be quickly accessed at all times, but can have certain periods of inactivity.